MIA was the vatlity sensor so many thought would be ready for a launch announcement. Nintendo just had to much to show and this years E3 did not appear to be the right time. Oddly it was shown at last years though, so we have to wonder where is the Little sensor and what surprises does it hold with 3DS taking all the attention.

Nintendo's Cammie Dunaway (star of the 2009 Vitality Sensor reveal) told Game Set Watch why: there was just too much other stuff. Yes, Nintendo "had a really packed agenda" and was too busy showing off another Metroid sequel, another Zelda sequel and, shocker, another Kid Icarus sequel to make room for something that is actually new. She continues that E3 is "noisy and adrenaline-filled, and loud and stressful, and it just didn't seem like the best environment to introduce a product that's really about relaxing." So, here we are, left sitting alone, index fingers coldly exposed to the elements, forced to find other ways to relax on our own.
http://www.engadget.com/2010/06/22/nintendo-explains-vitality-sensors-absence-at-e3-show-was-too/